Feasibility Study on Degradable Plastics for Logistics Packaging

Chen Guo

School of management, Tianjin University of Technology, Tianjin 300382, China

Keywords:

Degradable Plastics, Green Logistics, Logistics Packaging.

Abstract:

In recent years, the booming development of caller has changed people's shopping way and consumption

concept. At the same time, it also leads to the rapid development of logistics express industry, but this

development also brings a lot of logistics packaging waste. Under the background of national vigorously

advocating carbon neutrality, green and recyclable logistics packaging has gradually become a requirement.

This paper introduces some degradable plastics that can be used in logistics packaging. This paper analyzes

the advantages and disadvantages of using biodegradable plastics in logistics packaging and tries to provide

corresponding countermeasure.

1 INTRODUCTION

Goods can participate in circulation through the

means of packaging, packaging is a necessary link

of logistics.

Packaging in logistics is also divided into three

types, one is the packaging of the goods just

produced, this packaging is generally considered to

protect and beautify the goods. The second is

outsourcing packaging, which generally considers

the wholesale problem. Most goods will be sold

more than one piece, requiring larger outer

packaging for packaging, which is common in the

food and beverage industry. Third, express

packaging, considering the related problems in

logistics transportation, need to add a layer of

express packaging, to ensure that goods will not be

damaged in logistics transportation, but also need to

meet the delivery, sorting, transportation, delivery

needs.

In 2020, China's express delivery volume

reached 83.36 billion pieces, up 31.2 percent year on

year, showing that China has become a global

Courier power. With the rapid development of

express delivery, the demand for packaging has also

increased dramatically. From January to July 2021, a

total of 15.01 billion pieces of postal delivery

services were delivered, up 1.3 percent year on year.

At this rate, express packaging material

consumption is expected to reach 41.27 million tons

in 2025.Recently, the National Development and

Reform Commission and the Ministry of Ecology

and Environment issued the "14th Five-year plan for

Plastic Pollution Control Action Plan", which has

clear requirements for express packaging,

e-commerce express should realize secondary

packaging, using recyclable packaging instead of

traditional packaging.

As a new type of green

material, degradable plastic has become a trend of

large-scale application in e-commerce logistics.

2 DEVELOPMENT PROSPECT

OF DEGRADABLE PLASTICS

A biodegradable plastic is a material that can

degrade thermodynamically and dynamically over a

period of time. There are two kinds of materials that

have been applied in logistics packaging on a large

scale, one is biodegradable plastic, mainly polylactic

acid (PLA), the other is petroleum degradable

plastic, also known as thermoplastic biodegradable

plastic, mainly polyladipic acid (PBAT). Polylactic

acid (PLA) is produced from renewable plants by

saccharification to convert it into glucose,

fermentation with related strains, and synthesis

through complex chemical processes. It can be

completely degraded and absorbed by some

microorganisms after use, producing carbon dioxide

and water that will not cause pollution. It has good

thermal stability, good solvent resistance, can be

processed in a variety of ways, such as extrusion,

spinning, biaxial stretching, injection blow molding.

In addition to having good biodegradability,

Guo, C.

Feasibility Study on Degradable Plastics for Logistics Packaging.

DOI: 10.5220/0011178300003443

In Proceedings of the 4th International Conference on Biomedical Engineering and Bioinformatics (ICBEB 2022), pages 36-40

ISBN: 978-989-758-595-1

polylactic acid also has excellent glossiness,

transparency, hand feel and heat resistance. It is a

good green logistics packaging material. The current

global PLA production capacity exceeds 500,000

tons/year. NatureWorks is the world's largest

polylactic acid manufacturer with an annual

production capacity of 180,000 tons, accounting for

more than 30% of the world's polylactic acid

production capacity. The production of PLA is still

in the initial stage of development in China. Jiangsu

Yunyoucheng production line with annual output of

50,000 tons of PLA is the largest production line in

China. In recent years, new entrants have emerged in

the industry, mainly because of the promising

market prospects of lactic acid and its derivatives

lactide and polylactic acid in the field of

biodegradable new biological materials. Its

development has been successively included in

"863", "973", "Torch Plan", "13th Five-Year Plan",

"Made in China 2025" and "National Medium and

Long Term Science and Technology Development

Plan" key research projects.

The production process of polyglycolic acid is

synthesized by using adipic acid (AA), terephthalic

acid (PTA) and butanediol (BDO) as monomers

through esterification or transesterification and

polycondensation reaction in a certain proportion.

Direct esterification is a widely used production

process in China. The advantages of this method are

short process, high utilization rate of raw materials,

short reaction time and high production efficiency.

The disadvantage is that the reaction system is more

complex, the relative molecular weight distribution

is wide and difficult to control, the reaction

conditions are more demanding, the reaction

medium is more acidic, part of THE BOD

cyclodehydration reaction to form tetrahydrofuran

(THF), etc., which have influence on the product

quality. In addition, there are separate esterification

and series esterification processes, which have the

advantages of simple equipment, fewer intermediate

substances in the reaction system, narrow

distribution of relative molecular weight, easy

regulation of product viscosity, and reuse of waste

products. The disadvantage is that the product

quality may vary from batch to batch. Direct

esterification is a widely used production process in

China, which has high fracture elongation and

toughness, and excellent physical and chemical

properties. PBAT biodegradation mainly depends on

its chemical structure and degradation of the

environment, almost completely biodegradable,

some by microbial fermentation is degraded in

nature, some can make through chemical hydrolysis

and thermal degradation of polymer chain break in

depolymerization, there are also some

depolymerization intermediates by microbial

metabolism.

In recent years, China has issued a series of

policies to encourage the application and promotion

of biodegradable plastics, which has led to the

continuous expansion of the market for

biodegradable plastics in China. At present, China

has become a major producer of biodegradable

plastics in the world, and its products are exported

abroad, mainly to Europe and North America. It is

expected that with the growing demand of the global

degradable plastics market, the export and domestic

market size of Degradable plastics in China will

continue to increase. In 2020, the annual production

capacity of China's PBAT and PLA will be about

300,000 tons and 100,000 tons respectively.

According to industry estimates, by 2025, the

demand for degradable plastics in express

packaging, disposable plastic tableware, plastic

shopping bags and agricultural mulches will form a

total market space of about 2.5 million tons.

Accounted for in addition to the two bigger

biodegradable plastics, such as starch composite

plastic, poly (butyl diacid butyl glycol ester (PBS)

and poly hydroxy fatty acid ester (PHA) such other

accounts for the relatively small size of the market

of biodegradable plastics, through the model

forecast, can be expected to 2025 biodegradable

plastic future market demand will reach 3.3 million

tons, as shown in figure1.It is clear that

biodegradable plastics have a promising future.

Figure 1: Forecast of future market demand release

rhythm of degradable plastics (10k tons).

Feasibility Study on Degradable Plastics for Logistics Packaging

Figure 2: Comparative analysis of comprehensive performance of PLA, PBAT and LDPE

3 COMPREHENSIVE

COMPARISON BETWEEN

DEGRADABLE PLASTICS AND

TRADITIONAL PLASTIC

PACKAGING

Polyethylene (PE) is a widely used traditional

plastic, ethylene by polymerization of a

thermoplastic resin, is one of the most common

plastics, the annual production of more than 100

million tons of polyethylene resin, accounting for

34% of the total plastic market.PE is a typical

crystalline polymer with a melting point of 130℃ ~

145℃. It is characterized by tasteless, odorless,

non-toxic, matte surface and milky waxy particles. It

is also a major alternative to biodegradable

plastics.PE has excellent crystallinity, water vapor

barrier and weather resistance, which can be

collectively referred to as "PE characteristics". In

fact, currently common biodegradable plastics are

aliphatic polyesters, such as PLA and PBS, which

can be roughly regarded as PE containing ester

bonds. The ester bonds in its molecular chain give it

biodegradability, and the aliphatic chain gives it "PE

properties". Promising biodegradable plastics need

to be both biodegradable and "PE". Therefore, it is

necessary to compare the comprehensive properties

of biodegradable plastics and polyethylene.

As shown in the figure 2, PLA and PBAT have

different performance from PE. Each has its own

advantages and disadvantages, but none of them

fully possess the "PE characteristics". PBAT and

mechanical properties and the melting point of PE, it

can cover the basic PE in disposable products

industry, the application of PLA and intensity is

higher than the melting point of PE, but with

significantly lower tensile toughness and crystalline,

polymer relative molecular weight distribution of

the products is too wide, PLA itself for the linear

polymer, it makes the strength of the PLA material

often cannot meet the requirements, High

brittleness, low thermal deformation temperature

(54℃ under 0146MPa load), poor impact resistance,

only when it is toughened, crystallization promotion

and other modification can basically cover PE in the

disposable products industry application. In addition

to the basic characteristics of biodegradable plastics,

PLA also has its own unique characteristics.

Traditional biodegradable plastics are not as strong,

transparent and resistant to climate change as

ordinary PE.PLA has similar basic physical

properties to petrochemical synthetic plastics, which

means that it can be used to manufacture a wide

range of applications. PLA also has good gloss and

transparency, comparable to films made from

polystyrene, which cannot be provided by other

biodegradable products. PLA film has good air

permeability, oxygen permeability and

dioxide-carbon permeability. It also has the

characteristics of odor isolation. When PLA is

incinerated, its combustion heat value is the same as

that of incinerated paper, which is half of that of

traditional plastics (such as polyethylene), and the

incineration of PLA absolutely does not release toxic

gases such as nitrogen compounds and sulfides. The

body also contains lactic acid as a monomer,

indicating the safety of the breakdown product.

According to the analysis, theoretically, PLA and

PBAT can replace all disposable plastics. In

addition, although PLA and PBAT have overlapping

application fields, they have different characteristics.

For example, PLA belongs to hard plastics, while

PBAT belongs to soft plastics, which can be

approximately regarded as polypropylene and

polyethylene in petrochemical products. Moreover,

PLA membrane bags with poor blowing

processability are mostly blended with PBAT with

good toughness, which can improve the blowing

processability without damaging its

biodegradability.

4 EXISTING PROBLEMS AND

IMPROVEMENT MEASURES

OF DEGRADABLE PLASTIC

PACKAGING

Although biodegradable plastic packaging has a

promising development prospect, it is difficult to be

applied on a large scale in real life. The existing

reasons are three, one is that the development of

degradable plastic is not mature enough, a large part

of the main body involved in logistics is difficult to

product melting point/°C tensile strength /Mpa Elongation/％ Degradation rate Water vapor barrier Oxygen barrier

PLA 180 40-60 4-10 fast Average Average

PBAT 120 18 750 fast Poor Poor

LDPE 110 148 148 Non degradable Good Poor

ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics

accept this kind of emerging products. The solution

should be for the government to raise people's

awareness of environmental protection and change

people's view of degradable plastics through

relevant policies or publicity. The second reason is

the low bearing capacity of degradable plastic bags,

which to a large extent cannot meet the requirements

of logistics for multiple loading and repeated use.

The third and most important point is the cost factor.

Enterprises generally take maximizing profits as the

premise. According to relevant data, the price of

PLA and PBAT is 3-4 times that of mainstream

plastic PE, so using degradable plastic packaging

will compress the profit of logistics enterprises on

the premise of maximizing profits. If this kind of

excess expenditure is added to the logistics

demander, it may lead to the decline of the

competitiveness of similar products in the market.

Nowadays, the effective way to improve these two

reasons is to blend and modify them to improve their

physical and chemical properties and reduce the cost

of materials. Using other materials with lower cost

to blend and modify them can effectively reduce the

production cost of degradable plastics.

Several common blend modification, such as the

blend modification of PBAT and PLA, PBAT has

low tensile strength and modulus. PLA has the

characteristics of high strength and high modulus.

However, due to its inherent brittleness, low

elongation at break, low impact strength and easy

bending deformation, PBAT and PLA are blended.

The toughness of the material is improved while

maintaining its degradability. It solves the problem

of packaging damage caused by insufficient

hardness in logistics packaging.

PBAT can and

starch blend modification of polymer materials,

starch sources, cheap, can be completely

biodegradable, but its itself does not have

thermoplastic, and easy bibulous, not easy

processing, will join the rest of the PBAT matrix

modified starch, can greatly reduce cost and

accelerate the degradation rate of PBAT, to reduce

cost and solve the problem of resource shortage and

environment pollution. PBAT can also be filled and

modified with inorganic CaCO3. Nano CaCO3 has

the characteristics of small particle size and high

activity, and has a strong interface binding force

with the polymer.

It is usually used as a filler in

different polymers. Therefore, adding it into PBAT

to prepare degradable composite materials can

improve the performance of PBAT and greatly

reduce the cost.

For the production of biodegradable plastics

producers, there are a lot of technical barriers, PLA

exist two kinds of preparation methods, one is the

lactide ring-opening polymerization and direct

polycondensation method, the lactide ring-opening

polymerization is of the methods used by the

majority of enterprises, and this method the required

conditions are harsh, many domestic enterprises

subject to the technical level and production scale,

etc. There is no way to expand further. Another

reason is the lack of strong policy or legal support.

In foreign countries, the government set up a special

development fund, tax incentives and other policy

support the development of biodegradable plastics

industry, at present China in this respect, the support

to strengthen gradually, macroscopic policy support

more and more, although issued the "difference"

plastic pollution administrative action ", but the lack

of detailed rules, against the development of

production-oriented enterprises. Insufficient funds

and financing difficulties of enterprises. The scale of

Chinese biodegradable plastics enterprises is not

large enough, and the return cycle of biodegradable

plastics industry exceeds the expected design,

resulting in insufficient funds and financing

difficulties for enterprises. The evaluation system is

not perfect. Biodegradable plastics is a new industry,

many materials and products developed, there is no

product standards, to trade a lot of inconvenience

and disputes. Therefore, countries should be legally

clear biodegradable plastics in modern circular

economy system, the status and importance to give

strong support on policy, on the application and

development of biodegradable plastic products

subsidy policy, refine on tax preferential measures,

and to set up special national development fund,

lead into the various funds, to promote the

development of degradable plastics industry.

Relevant government departments assist enterprises

and scientific research institutions in technological

innovation and promote the research, development

and popularization of mature technologies; Actively

develop cheap and widely sourced raw materials,

using mature technology and processing processes;

In order to reduce the production cost, it is necessary

to find efficient strains and low-cost media, develop

the best fermentation process and molding process

equipment. Strengthen investment in biodegradable

plastics standards, testing technology and other

aspects, improve product standards.

Feasibility Study on Degradable Plastics for Logistics Packaging

Figure 3: An illustration of a fully biodegradable plastic

bag.

5 CONCLUSION

As policies continue to increase, it has gradually

become a requirement that biodegradable plastics

replace traditional plastics as logistics packaging.

Relying on its environmental protection, energy

saving, recyclability and other properties,

biodegradable packaging perfectly conforms to

modern people's green and environmental ideology,

and also conforms to my country's sustainable

development strategy, and its future market is very

broad. Although the development of degradable

plastics is not yet mature enough, and related

technologies are not fully mastered, as the global

demand for degradable plastics continues to expand,

the degradable plastics industry will be forced to

further develop and improve. The emergence of

degradable packaging materials not only conforms

to the development theme of green and

environmental protection, but is also a new trend in

the development of logistics packaging materials,

and also has a profound impact on green logistics.

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ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics